1. Field of the Invention
In one aspect, this invention relates generally to systems and methods for controlling the behavior or motion of a drill string and/or bottomhole assembly to optimize drilling operations.
2. Description of Related Art
To obtain hydrocarbons such as oil and gas, boreholes are drilled by rotating a drill bit attached at a drill string end. Conventionally, the drill bit is rotated by rotating the drill string using a rotary table at the surface and/or by using a drilling motor in a bottomhole assembly (BHA). As can be appreciated, the cutting action of the drill bit against the earthen formation and the rotation of the drill string within the wellbore can produce a number of vibrations and motion that can cause a number of non-beneficial conditions such as a reduction in the effectiveness of the cutting action, damage to tooling, reduction in tool life, impairment of the effectiveness of downhole tools, etc.
Conventionally, a number of solutions have been applied to handle these non-beneficial conditions. For example, some tools are provided with housings or other structures that attempt to isolate the tooling from shock and vibrations. Other solutions include positioning tooling in areas where vibrations are expected to be the lowest. Additionally, tooling such as passive shock absorbers and stabilizers have been devised to absorb or ameliorate potentially harmful vibrations and motion. One drawback to such conventional systems is that they cannot in a real time or near real time basis adapt to the dynamic drilling environment. For example, a conventional shock absorber is constructed to have a fixed range of frequency and amplitude absorption. Such a shock absorber may have diminished value if the damaging vibrations are outside the range of the pre-set frequency and amplitude.
Another solution to handling damaging vibrations and motions is to alter drilling parameters such as weight on bit, drill bit rotation speed, drilling fluid flow rate, etc. until the damaging vibrations are minimized. It will be appreciated, however, that such alterations may result in drilling at non-optimal conditions, e.g., reduced rate of penetration.
The present invention address these and other needs relating to the above-described problems.